The disclosed invention generally relates to digital-to-analog converters, and is particularly directed to a digital-to-analog converter having reduced sensitivity to first order integrated circuit processing variations and further having improved integral linearity.
Digital-to-analog converters are utilized to provide an analog signal, such as a voltage, as a function of a digital input. Digital-to-analog converters typically include binary weighted elements (e.g., capacitors, resistors, or current sources) which are selectively switched as a function of the digital input. However, such binary weighted elements need to be extremely precise and/or well matched to avoid integral non-linearity that would cause erroneous analog output signals.
In the processing of integrated circuits, first order processing variations result in nominally identical elements at different locations having different values. In digital-to-analog converters, such first order variations in the weighting elements (e.g., resistors, capacitors) causes integral non-linearity.